Need help with small solar project

[Community Alumni]

Hi folks, this isn't RV related but I'm hoping the solar experts in this forum can lend a helping hand with my project.

I want to install a wireless IP webcam in a location where there are no electric outlets nearby.

The webcams consume 4 to 7 watts and are powered by 5 to 12V DC current. I want to install a solar panel and a battery that will power the camera 24/7 but don't know the size of solar panel and battery required to make it work. I also don't know if I'll need peripheral components such as a charge controller.

I have an old 125W automobile-type inverter with a cigarette-lighter plug lying around that I thought I could use and just connect the power adapter that comes with the webcam to the inverter.

For aesthetics reasons, I'm hoping a motorcycle or UPS backup battery will work so I can house all the necessary components in a small weather-resistant enclosure near the webcam.

If it helps determining the size of the solar panel and battery, the webcam will be installed in a full-sun location in the desert.

Thanks in advance for your help.

[Community Alumni]

Thanks for all the tips, they are greatly appreciated.

[valhalla360]

Let's assume 7w and it runs 24hrs per day (as someone mentioned, far better to actually measure), that works out to 168w or about 14 amp-hr at 12v. Figure 20amp-hr to account for inefficiency. That results in needing a 40amp-hr battery as you can't take a lead acid battery below 50% without damage. Wouldn't be a bad idea to bump it up to 80amp-hr, so if you have a couple overcast days it doesn't kill the battery.

That's likely going to exceed what a lawn tractor battery can do. It might work for a week or so as the battery fully discharges but eventually it will kill the battery.

You might need to bump it up a touch for the charge controller. They don't take much but you are working with a really small system so it might be an impact.

If you go with a 12v camera, you can wire it directly to the battery without a converter which is simpler and more efficient.

As far as the solar panels, you need to put out about 200watt-hr per day. Figure you get about 4hr total of the rated output (it varies across the day and you almost never get the full rated output), so figure at least a 50w panel. Bumping up to 75w would be a good idea to help recover after an overcast day.

[TenOC]

Check out Harbor Freight for a Solar system. or

Solar System for gate opner

[theoldwizard1]

gemsworld wrote:
For aesthetics reasons, I'm hoping a motorcycle or UPS backup battery will work so I can house all the necessary components in a small weather-resistant enclosure near the webcam.

Either will work, but neither are really the best for the job and may not have a long life. I don't know of any SMALL true deep discharge lead acid batteries.

Li-Ion is a possibility, but it will run your cost up ! First, you will need a charge controller that will handle Li-Ion batteries. Then you need the batteries themselves. Li-Ion batteries have a nominal 3.7V but must be charged at above 4.0V. so 4 Li-Ion batteries in series will need to be charged at more than 16.0 Your inverter might not like that. Adding 3 diodes in series between the positive of the battery pack will get you to about the proper voltage.

You will likely need 3 or 4 four battery packs, wired in parallel. Expensive, but they will last a very long time.

[azrving]

gemsworld wrote:
I came across this YT video that may help out rjxj with his trail cam:

Trail Cam Solar Panel DIY

Thank you. I subscribed. That voltage regulator is a nice find. That's where I went wrong with my set up.

[Community Alumni]

I came across this YT video that may help out rjxj with his trail cam:

Trail Cam Solar Panel DIY

[GordonThree]

If you just want to buy something without math getting in the way, a 100 watt panel, cheap pwm controller and the biggest battery in your price range.

Something like a GoalZero kit would work, although they are wishy-washy on actual capabilities and capacities.

[Community Alumni]

Thanks for the prompt replies.

The reason the wattage varies from 4 to 7 watts is based on the different cameras that I might use. Same for the 5 to 12V DC current.

For the sake of simplicity, what would I need in terms of solar panel and battery if I used a camera that uses a constant 7 watts 24/7?

[pianotuna]

It would be best to know the power demands for six days. Size the battery from that information, and then size the panels to keep the bank full.

Without knowing the energy needed any answer would be just a guess.

[ncscz]

I used an earlier version of a Moultrie Power Panel to power an Wi-Fi POE bullet cam. The camera was not streaming. I used it to send photos to an ftp server when motion was sensed. I ended up moving the camera to a different location that had power available so I did not use it over a winter, but I do not believe the batter would last over night in the cold temperatures and limited sunlight of December & January.

[GordonThree]

Sounds like a fun project.

First off, get a multimeter and measure the actual current draw of the web cam. Cut the DC side of the power cord and patch the meter in series with one of the conductors, so power flows from the wall adapter, through the meter, through the camera and back to the adapter. If you don't want to do this, and your range is 4 to 7 watts, lets just round that up to 10 to make the math easy.

The battery needs to run the camera, well, most of the time. 10 watts times 18 hours (conservatively) is 180 watt-hours. 180 watt-hours divided by 12 volts is 15 amp-hours... that's about the size of a garden tractor battery (I don't know what size a motorcycle takes, is it similar?)

You want a panel that can push out 180 watts in 6 hours for the battery, plus another 60 watts for the camera... 240 watt-hours divided by 6 hours is 40 watts. You want a 40 watt panel, at a minimum.

Yes, you want a charge controller. It doesn't need to be MPPT, that won't help much at these lower power levels... any 'ol cheapy off eBay will be fine. The controller is more to keep the battery from being destroyed if too much power comes in.

Lastly, you don't want or need to use an inverter. Instead get an adjustable DC-DC converter, like a DROK and set it to whatever voltage your camera wants. This will save on waste caused by the inverter and waste caused by the wall adapter.

[azrving]

I tried something similar when trying to power some trail cams with other than alkaline batteries. I bought some small motorcycle like batteries off ebay that said AGM and they died quickly. The charger that came with them although rated correctly seemed to blow out one cam so I threw all that stuff in the trash and went back to duracell alkaline after also trying the Amazon alkaline AA batteries. Amazon AA are not comparable to Duracell. They are cheaper so given their performance they may be cost effective for some.

I will also look forward to others ideas. Thanks for posting.